The invention provides a heating substrate which has soft feeling, less weight and is foldable.
A conventional electric blanket, as shown in FIG. 1, includes thermal insulators 1 each having a film 2 thereon. The heating wire 3 formed by winding a filament 3a made of nickel chromium alloy or iron chromium alloy around a fiber core 3b and encapsulating the filament 3a and the fiber core 3b with plastic wrappings 3c. The heating wire 3 is wound in a form of xe2x80x9cSxe2x80x9d on one of the films 2. One fiber net 4 is attached on the heating wire 3. Thermal insulators 1 cover the fiber net 4, such that the heating wire 3 is between the thermal insulators 1. Finally, the whole structure is encapsulated with plastics 5 to achieve the conventional electric blanket.
The heating wire 3 made of nickel chromium alloy or iron chromium alloy is rigid. The larger the number of the filament 3a is, the more rigid the heating wire 3 is. Therefore, the electric blanket obtained in the way recited above cannot fit a user""s body and cannot give soft feeling to the user when in use. Additionally, the filament 3a made of nickel chromium alloy or iron chromium alloy increases the weight of the electric blanket and the difficulty to fold. Furthermore, the inner thermal insulators 1 are not bound to the plastic 5, often resulting in the inner thermal insulator being distributed unevenly.
A principal objective of the invention is to provide a heating substrate that includes a thick flexible fiber layer and a plurality of flexible graphite threads. Each of the flexible graphite threads consists of a plurality of flexible graphite fibers. The graphite threads are wound and stitched on the thick flexible fiber layer. The substrate formed by graphite fibers has less weight and is not easy to be broken. Furthermore, a plurality of slots is formed on the thick flexible fiber layer for binding external wrappings. Thereby, the flexible fiber layer is prevented from being distributed unevenly.
To provide a further understanding of the invention, the following detailed description illustrates embodiments and examples of the invention, this detailed description being provided only for illustration of the invention.